Zeolite membrane characterisation

Geus E.R., Preparation and characterisation of composite inorganic zeolite membranes with moleculare sieve properties. Ph.D. Dissertation, Technical University of Delft, The Netherlands (1993). 

Silicalite-1 membranes, supported on porous alumina ceramic discs, have been prepared by two different routes. In the first the zeolite membrane has been formed by in situ hydrothermal synthesis. Secondly a layer has been formed by controlled filtration of zeolite colloids. To optimise membrane stability, conditions have been established in which penetration of zeolite into the support sublayer occurs. The pore structure of these membranes has been characterised by a combination of SEM and Hg-porosimetry. The permeabilities of several gases have been measured together with gas mbeture separation behaviour. 

Zeolite membranes form the most recent branch of the inorganic membrane field for which characterised and properly described real microporous zeolite... 

S. Xiang and Y.H. Ma, Formation and characterisation of zeolite membranes from sols, in Yi Hua Ma (Ed.), Proceedings of the 3rd International Conference on Inorganic Membranes 10-14 July 1994, Worcester. Worcester Polytechnic Institute, 100 Institute Road, Worcester, MA 01609, USA, pp. 95-105. 

Fig. 6. Principle of permporometry for the dynamic characterisation of zeolite membranes. When the partial pressure of n-hexane (p/p ) increases, it blocks first zeolite pores and then larger and larger defects sizes, thus blocking progressively the permeation of He.

Other groups also work on similar principles for the characterisation of zeolite membranes by the so-called Dynamic Desorption Porosimetry or by dynamic desorption of adsorbing species [130],... 

J. Hedlund, F. Jareman, The synthesis, characterisation of thin MFI membranes in Proc. 3rd lnt. Zeolite Membrane Meeting, R. Noble (Ed), Breckenridge, CO USA, July 25-28, 2004. 

The synthesis and characterisation of silicalite-1 membranes on porous alumina ceramic supports have been described here. The growth of the silicalite-1 membrane could be optimised by controlling the hydrothermal synthesis conditions. It has been shown that by controlling the synthesis conditions it is possible to optimise the growth and structure of silicalite-1 membranes. Thus at lower synthesis temperatures (150 °C), the growth of silicalite inside the macro-pores of the ceramic support is favoured. At higher temperatures (190 °C), thick, well crystallised zeolite layers develop from the surface of the support. A more stable membrane is... 

E. R. Geus, M.J. den Exter and H. van Bekkum, Synthesis and characterisation of zeolite (MFI) membranes on porous ceramic supports. /. Chem. Soc. Faraday Trans., 88 (1992) 3101-3109. 

Meng Dong Jia, K.V. Peinemann and R.D. Behling, Ceramic zeolite composite membrane preparation, characterisation and gas permeation. /. Membr. Sci., 82 (1993) 15-26. 

A series of more sophisticated permeation techniques have been recently proposed in order to better characterise the quality of the membrane and to evaluate qualitatively the contribution of non-zeolite pores to the transport. A number of methods derived from permporometry [125] are under study [111,129], The method used in [111] consists in measuring the permeance of an inert gas such as He through a MFI membrane, while increasing the partial pressure (p/pn) of a condensable gas which can enter into the zeolite pores, such as w-hcxanc (Okmaic = 0.43 nm). Zeolite pores arc then blocked first by -hexane adsorption, and when the proportion of n-... 

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